The present invention relates to an improved elevator cage position detecting device.
In operating an elevator, detection of the position of the cage is an essential function which is carried out by a floor selector. A variety of floor selectors are available. Recently, an elevator position detecting device utilizing an electronic computer as shown in FIG. 1 has been employed. In FIG. 1, reference numerals 1 and 2 designate the first floor and the second floor, respectively, 3 an engaging cam member disposed between the first floor 1 and the second floor 2 in the elevator cage passage, 4 the cage of the elevator, 5 a position-between-floors detector, 6 a converter for converting an input into data in suitable form for an electronic computer, 7 the electronic computer, and 8 a floor memory for storing cage positions which are calculated by the electronic computer 7. Data can be written into or read out of the floor memory 8.
The converter 6 is provided to convert an input signal to an information signal for electronic computer microprocessor. The converter 6 (FIG. 7) includes a plurality of sections 6a, 6b, . . . , 6n each having resistors 61 and 62 and a photocoupler 63. The blocks 6a, 6b, . . . produce logic level signals (6a-1), (6b-1) in response to the ON-OFF states at terminals 64, 65, . . . , respectively. V.sub.1 and V.sub.2 designate power source voltages.
In the device shown in FIG. 1, the electronic computer is Model 8085A manufactured by Intel Co. although it may, for instance, be replaced by Model M6800 manufactured by Motorola Co. or Model Z80A manufactured by Zilog Co. or a digital computer such as a microcomputer. The electronic computer 7, which is a microcomputer in this device, includes an input port 71 (Intel Co. Model 8212), a central processing unit (CPU) 72 (Intel Co. Model 8085A), an interruption period controlling timer 73 (Intel Co. 8155), a read-only memory (ROM) 74 (Intel Co. 2716), a random access memory (RAM) 75 (Intel Co. 2114A), and an output port 76 (Intel Co. 8212). The floor memory 8 may be the same random access memory (RAM) type (Intel Co. 2114A) also.
When the cage 4 is at the first floor 1, the content of the floor memory 8 is a value representative of the first floor 1. While the cage is moving upwardly, the detector 5 engages the cam 3 generating an output. The output is applied to the converter 6, the output of which is applied to the central processing unit 72 through its input port 71. In the central processing unit 72 a value of "1" is added to the content of the floor memory 8 in accordance with the output of the detector 5 and the directions of run of the cage 4. That is, the content of the floor memory 8 is changed to a value corresponding to the second floor. In the case where the cage 4 moves downwardly from the second floor 2, the detector 5 engages the cam 3 again, as a result of which "1" is subtracted from the content of the floor memory 8. That is, the content of the floor memory 8 is changed to the value corresponding to the first floor.
Thus, the calculated cage position (hereinafter referred to as "a cage position signal" when applicable) changes in synchronization with the actual cage position. Usually, the detector 5 is maintained engaged with the cam 3 for a certain period of time. Generally, the central processing unit 72 decides that the detector 5 has engaged the cam 3 either when the output of the detector changes from "open" to "closed" or when the output changes from "closed" to "open" at the instant the detector 5 engages the cam 3 so that only at that time is data received and supplied for calculation.
If, during elevator inspection operation, the cage vibrates near the cam 3, the direction of movement of the cage 4 may be reversed with the detector 5 maintained engaged with the cam 3. If, in this case, the cage is moving upwardly to cause the detector 5 to engage the cam 3, then "1" is added to the content of the floor memory 8 at the time instant when the detector 5 engages the cam 3. If the cage is continuously moved upwardly to allow the detector 5 to disengage from the cam 3 and is then moved downwardly, "1" is subtracted from the content of the floor memory 8 when the detector 5 engages the cam 3 again. However, if the direction of movement of the cage is reversed with the detector 5 maintained engaged with the cam, then the aforementioned subtraction is not carried out as a result of which the cage position signal is different from the actual cage position by as much as one floor.
Accordingly, an object of this invention is to provide an elevator position detecting device in which the above-described difficulty accompanying a conventional elevator position detecting device has been eliminated. Specifically, it is an object of the invention to provide a position detecting device in which, even if the cage is irregularly moved between floors, the cage position signal will always coincide with the actual cage position.